CVE-2021-3444

The bpf verifier in the Linux kernel did not properly handle mod32
destination register truncation when the source register was known to be 0.
A local attacker with the ability to load bpf programs could use this gain
out-of-bounds reads in kernel memory leading to information disclosure
(kernel memory), and possibly out-of-bounds writes that could potentially
lead to code execution. This issue was addressed in the upstream kernel in
commit 9b00f1b78809 (“bpf: Fix truncation handling for mod32 dst reg wrt
zero”) and in Linux stable kernels 5.11.2, 5.10.19, and 5.4.101.

Notes